Radiation polymerizble coating compositions are described in U.S. Pat. No. 4,116,786 to Hodakowski, in which the compositions contain an acrylate-capped polyether urethane, a low molecular weight polyfunctional acrylate, a monofunctional acrylate and a small amount of a polyether-functional polysiloxane.
Also, radiation curable coating compositions are described in U.S. Pat. No. 4,301,209 to Lorenz et al, in which a polytetrahydrofuran, polycaprolactone polyols and other polyols are reacted with a diisocyanate to form an isocyanate terminated prepolymer and the isocyanate terminated prepolymer is then capped with a capping agent having terminal amine or hydroxy group and also contains an acrylic acid or methacrylic acid moiety.
Radiation polymerizable acrylate-functional polysiloxanes in which the acrylate containing group is bonded to a silicon atom via a silicon-carbon-nitrogen linkage is described in U.S. Pat. No. 4,606,933 to Griswold et al.
Generally, the compositions described in the Griswold patent are not soluble in commercially available multi-acrylated monomers and acrylated oligomeric compositions. This often results in nonuniform coatings which have undesirable physical properties.
Therefore, it is an object of this invention to provide a process for preparing acrylate-functional organopolysiloxane-urethane copolymers. Another object of this invention is to provide novel acrylate-functional organopolysiloxane-urethane copolymers that are reactive under radiation conditions even in the presence of oxygen. A further object of this invention is to provide novel acrylate-functional organopolysiloxane-urethane copolymer compositions which are soluble in multi-acrylated monomers and acrylated oligomeric compositions.